Any own an 11/725...?

I am something of a PERQ-fanatic, so I am well aware of this. The classic PERQs have user-modifyable microcode, and the hardware is not designed for a particular isntruction set (there is no hard-wired instruction decoding at all, unlike, say, a PDP11/45), so you can pretty much do what you like. Under POS (PERQ OS or Pascal OS, depending on which book you read), you were not expected to write any machine or assembly langage (Q-codes). The assember was not included in the OS distribution, and the manual doesn't really epxlain the Q-codes. But the microcode assember and placer were included, the manual does describe user-written microcode. For some things, like directly accessing I/O ports (say for custom hardware -- like the tape streamer interface hack) you _have_ to use microcode on the PERQ. But you can also use it to speed up critical routines in your program (just don't try and improve the raster operation microcode, you won't do it. Period.) -tony